Congressional candidate Kirk Adams' campaign manager has apologized for making an off-color joke about senior women on Facebook.

Chad Heywood made the comment Wednesday as part of a lighthearted discussion about veteran entertainer Pat Boone, who is supporting Adams, a former Arizona House speaker, in his 5th Congressional District Republican-primary race.

Boone, a singer whose version of "Love Letters in the Sand" was a No. 1 hit in 1957, recorded a robocall message on behalf of Adams that voters heard earlier in the week.

One participant in a Facebook forum about East Valley politics mentioned that Boone has the same effect on "the senior vote" that current pop sensation Justin Bieber has on pre-teenagers.

"DUDE, you have no clue how many older ladies just mailed Kirk Adams their panties ... mail box was full today," Heywood wrote in response.

The campaign of Adams' GOP rival, former U.S. Rep. Matt Salmon, quickly demanded that Adams apologize for Heywood's "rude and offensive comments."

Former state Sen. Chuck Gray, a Salmon supporter, chimed in with a written statement noting that Heywood's remark "was made in reference to female voters in the 5th Congressional District, and it deserves immediate condemnation and a public apology from Kirk Adams for allowing this type of behavior to be tolerated in his campaign."

Heywood expressed remorse over the remark in a follow-up Facebook post.

"I apologize for my inappropriate comment earlier today on a private Facebook page," he wrote. "It was weak attempt at humor that I regret. In no way does it represent the values of Kirk Adams or his campaign. I regret the comment."

Adams responded to the controversy Thursday by calling on Salmon to keep the campaign focused on the issues and their records. Adams accused Salmon of trying to use the aide's Facebook gaffe to avoid talking about topics such as his lobbying and past donations to Democrats.

"Mr. Salmon is sending out his first press release in the entire month of August about an inappropriate joke my staffer made on his personal Facebook page," Adams said in a written statement to The Arizona Republic. "The comment was a clear lack in judgment, and my staffer has apologized."

Arizona's 5th Congressional District includes Gilbert and parts of Mesa and Chandler.